Demystifying Caffeine
By Morgan Davis, RD, LDN
Caffeine has pulled a good deal of negative media attention over the past month, namely the caffeinated beverage 5-hour energy after the Food and Drug Administration (FDA) received reports of deaths associated with the product. Although overdosing on caffeine would be highly unlikely, energy drinks and their ingredients are not regulated by the FDA since they are considered dietary supplements. For this reason, producers of beverages like 5-hour Energy and Monster Energy drinks are not required to list caffeine content on the labels. The FDA has found that the caffeine content in these drinks ranges greatly, from 160-500mg per serving.
Although the new media attention has cast a dismal light on concentrated caffeine supplements, it should be understood that caffeine is also found in a multitude of other foods and beverages, which unlike dietary supplements, are regulated by the FDA. Caffeine, in one form or another, is used by over 75% of the American population. And overwhelming research has pinpointed certain health benefits from caffeine. Let’s take a closer look at this substance that is so often under fire.
How it works
Caffeine is a naturally occurring compound. The chemical process in which caffeine stimulates brain function is actually similar to the method in which drugs such as cocaine and heroin work. When caffeine is ingested, the molecules will bind with adenosine (a compound that acts as a sedative) receptors in the brain. Serum levels of adenosine increase during hours you are awake and decrease when you sleep. If you are sleep deprived, adenosine will be more concentrated making you sleepier. When adenosine binds to receptors, nerve cell activity slows, brain blood vessels dilate, and you become drowsy. When caffeine is ingested, it competes to bind to adenosine receptors; this decreases the effect of adenosine, making you feel more alert. Beware if you are a regular caffeine user- your body will generate more adenosine receptors, essentially building a tolerance to your typical level of caffeine use. In fact, the negative feelings (headache, mental fogginess, drowsiness) a habitual caffeine user may experience if they go without for a day or two are related to withdrawal symptoms.
The “Bad”
Despite the negative media attention involving energy drinks, caffeine itself would be very difficult to overdose on. However, there are additional reasons to make sure caffeine intake is moderated.
- 1. Caffeine causes increased heart rate. This is one of the most obvious side effects. To someone who is more sensitive, or who does not typically indulge in the stimulant, even small amounts of caffeine can cause uncomfortable jittery feelings.
- 2. Caffeine can lead to disrupted sleep cycles. Relying on caffeine to make up for inadequate sleep can result in a cycle that is hard to break. Caffeine must be metabolized by the body, just like anything else consumed. Some people metabolize the stimulant slower than others, meaning there may still be enough caffeine in the body at the end of the day to interrupt sleep cycles. This obviously causes less quality sleep and more need for caffeine.
- 3. Caffeine should be avoided during pregnancy. Caffeine intake of greater than 200mg in a day may have harmful effects related to fetal growth and risk for miscarriage.The FDA recommends that pregnant woman avoid caffeine-containing foods and beverages, or use sparingly.
The “Good”
There are plenty of pros to even out the negatives that come with caffeine consumption.
- 1. Caffeine wakes us up. The most obvious benefit of caffeine is its ability to neutralize the increased adenosine that is produced during periods of inadequate sleep. This causes the caffeine consumer to become less sleepy and more alert. As mentioned earlier, the brain will create more adenosine receptors in the situation of chronic caffeine use, meaning more caffeine is needed for the same effect if you are a habitual user.
- 2. Caffeine stimulates the brain and elevates mood. Caffeine stimulates the release of dopamine, which causes feelings of pleasure and well-being. Increases in cognitive function are found to be greater in people who are not habitual users of caffeine.
- 3. Caffeine increases physical performance. In endurance sports (long-distance running, swimming, cycling, etc) caffeine has been shown to improve performance. The mechanism is not quite clear, but some theories are that caffeine can reduce the feeling of muscle pain to allow us to feel better and exercise longer, or that caffeine triggers the body to burn fat for fuel instead of limited carbohydrate stores. Refer to the link for the Gatorade Sports Science Institute below to learn more about caffeine and exercise.
- 4. Caffeine eases headaches. Dilated blood vessels in the brain are associated with headaches. Caffeine works to constrict these vessels, helping to decrease the perceived pain. This is why you find caffeine in medicines such as Excedrin.
- 5. Caffeine intake may reduce risk for some diseases. As mentioned above, caffeine can increase cognitive function; now there is more scientific evidence that caffeine might also lower risk for developing Alzheimer’s dementia. Several studies have found that caffeine may also be protective against Parkinson’s disease, and possibly decrease the related motor symptoms in someone in which the disease is already present. A possible explanation is because in Parkinson’s disease, dopamine-producing nerve cells are lost. Caffeine counteracts this by stimulating the release of dopamine. Another potential caffeine benefit is reduction in risk of developing gallstones by stimulating the gallbladder to contract and expel the compounds that form gallstones.
The bottom line
Most will agree that moderate caffeine consumption has its benefits. The definition of moderate consumption is debatable, but in general is considered about 300mg per day (on average, about 3 cups of coffee). See the link below to find the caffeine content in popular foods and beverages. If you are feeling jittery, anxious or are having gastrointestinal symptoms associated with your caffeine intake, this may be your body’s signal telling you to cut back on your daily amount.
Caffeine and Exercise
http://www.gssiweb.com/Article_Detail.aspx?articleid=33&level=3&topic=7
Caffeine Content in Popular Foods and Beverages
http://www.cspinet.org/new/cafchart.htm
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